Energy Star Rated Windows Explained

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What Are Energy Star Rated Windows?

Energy Star rated windows are certified by the NFRC or National Fenestration Rating Council and must meet stringent criteria for energy efficiency. The "Energy Star" designation came about as a way to promote replacement windows that were better for the environment. The certification is just for home windows -- it's on all kinds of products: refrigerators, washers, dryers, doors, etc.

Not only do Energy Star rated windows save money in terms of homeowner's monthly utility costs, but they also provide homeowners with a federal tax credit. So it's a true win-win-win in my book. Let's dive into the benefits, features, costs and other considerations.

Dane - Site Editor - Updated In October, 2023

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Basics Of The Program

Energy Star Window Costs

Federal Rebate

NFRC Label

Importance Of The Certification

ES Windows Cost Estimator

Homeowner Questions And Answers

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Basics Of ESRWs

ESWs are designed to optimize thermal performance, ensuring that homes remain comfortable throughout the year. This in turn minimizes the need for excessive heating or cooling. These window series are built with advanced technologies that reduce heat transfer, prevent air leakage, and block harmful ultraviolet (UV) rays.

Energy Star rated windows are dual paned, separated by insulating gas fills such as argon or krypton. This design improves the window's overall thermal efficiency. Additionally, low-emissivity (low-E) coatings are applied to the glass surface that reflect heat back into the room during colder months and block unwanted solar heat gain during warmer months.

ESRWs are carefully sealed to minimize drafts and maintain airtightness. Low air infiltration rates are one of the most important factors in terms of achieving a high energy efficiency.

In addition to thermal performance, Energy Star rated windows offer UV protection. These low-e coatings block a significant portion of UV rays, and protect furniture etc. from fading or discoloration.

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Energy Star Windows Prices

Energy Star rated windows have NO SET PRICE, although they will (usually) be more expensive than non Energy Star options. To get the ES certification, manufacturers have to make at least a decent window, so it makes sense that they are going to be pricier than more or less your worst vinyl windows on the market.

Basically, there is simply no way to answer the question of what do Energy Star windows cost. The reason is there are so many ES options out there. It's like asking what does a car cost. There is a massive range in price.

Instead let me give you a price list based on the most popular window materials -- please note: all of these replacement window costs are for a normal sized opening with retrofit installation. Essentially what I did below was lop off the lower end of the normal price range.

Energy Star Vinyl Window Costs 2023
-- $500 to $1200 fully installed --

ES Fiberglass Window Costs In 2023
-- $800 to $1800 fully installed --

ES Wood Window Costs In 2023
-- $1200 to $2500 fully installed

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Federal Rebate

Energy Star windows are eligible for a federal rebate of up to $3200 (in 2023). Whether or not they're eligible will depend on the specific climate zone in which you live. There are four climate zones in the United States: Northern, North-Central, South-Central, and Southern.

Each zone has unique specifications that must be met in order to qualify for the ES designation. Quality window companies should have a solid understanding of the specific performance date required within their zones.

NFRC Label

Any window that is ENERGY STAR qualified will have a distinctive sticker on the front or side -- its easy to find in most cases. The sticker includes manufacturer name, model number, the blue logo, and the performance data on the NFRC label. This performance data can be split into five parts:

U-Factor: U-factor, or U-value is a measure of a window's heat loss. U-factor ranges in value between 0.10 and 1.3 - the lower the number, the better the energy efficiency.

Real World Examples Of U-value:

Soft-Lite Elements Window - 0.19 (outstanding U-value)

Sunrise Restorations Window - 0.27 (impressive U-value)

ProVia Integra Series - 0.30 (average U-value)

Silverline V3 Series Window - 0.35 (not impressive U-value)

Air Infiltration: Air infiltration or AI is a measure of how much air leaks through the window unit. Air infiltration ratings range between 0.01 and 1.0. The lower the AI rating, the less air enters through the unit and the better the window unit.

Real World Examples Of Air Infiltration

Vinylmax Hyde Park - 0.17 (not very impressive)

Great Lakes EcoSmart - 0.06 (impressive)

HiMark 800 Series - 0.01 (outstanding)

Solar Heat Gain Coefficient: Solar Heat Gain Coefficient measures the heat that enters through the window glass and frame (mainly through the glass). SHGC window ratings range from 0 and 1.0. The proer SHGC level will depend on where you live - so it's not a set number at all. If you live in a hot climates, you would want window glass that reflects more heat and has a lower SHGC. Conversely, if you live in a cold climate, you would want to let more heat enter through the glass and therefore has a higher SGHC. The main way SHGC is modulated is through low-e coatings on the window glass.

Visible Transmittance: Visible Transmittance is the measure of how much light a window lets in. VT ranges from 0 and 1. The higher the visible transmittance rating, the more natural light will be allowed to flow into the room. Clear glass will have a high VT as it lets in lots of light, but is not very energy efficient. A low-e3 glass (very energy efficient) will have a low VT. There is a balance here that consumers will have to take into consideration -- how much heat do you want to stay out of the house and how much light do you want to allow in.

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Importance Of Energy Star Rated Windows

There is actually little importance for me of having this designation on a window. I've seen the label on some series that I would consider to be pretty poor quality. I am MUCH more interested in seeing the air infiltration rate and design pressure rating of a replacement window. These data points are much more important in terms of making your home energy efficient. Still, an energy star rated window does mean it has passed that threshold set forth by the certification team.

For homeowners, Energy Star rated windows are probably more important because of the federal tax credit. And I completely get this. Purchasing Energy Star rated windows can make homeowners eligible for a federal tax credit of up to $3200, which is a pretty sweet savings. My only point here is that there are more important factors (long term that will affect your home's energy efficiency and how much you have to pay for repairs etc.) such as AI, DP, and SHGC.

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Energy Star Windows Cost Estimator

Our ES windows cost estimator can provide you with basic pricing -- basically industry standard pricing. What the calculator can't provide is a fair market price for your window replacement project. This can only be achieved through getting multiple leads from top quality companies in your area. Play around with the cost estimator and shoot us an email with any questions you might have.

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Energy Star Window Labels

Hi Dane, very nice job with your youtube channel. I did subscribe to it.

Whenever you have a chance i'd appreciate any quick opinion you have on Energy star ratings and whether i should be "bothered" by any window manufacturer that doesn't have the Energy Star label if energy savings, etc are important to me?

What i'm wondering is maybe the NFRC labeling should be sufficient and trustworthy and therefore EnergyStar isn't such a big deal? I don't believe the Okna 500 window is EnergyStar, and i believe you think highly of that window, so that's one reason i'm thinking maybe NFRC labeling is sufficient.

Then again in terms of the federal tax credit that i'm pretty sure is still available, my guess is only EnergyStar windows are eligible for the credit, and while the credit isn't a "huge" amount of savings, it's indeed "some" savings...

Thanks Dane.

Mike - Homeowner - from 2023

[Site Editor's Answer]

Mike, thanks for the youtube subscription, every little bit helps!

So the EnergyStar designation doesn't REALLY matter -- except for the federal credit, which does matter because that's money in your pocket. I do find it weird that certain windows don't make the grade, especially one like the Okna 500 window -- it's ticky-tacky because the series is awesome and nothing has changed intrinsically about the energy efficiency numbers or date.

I haven't spent as much time looking at the different qualifications for EnergyStar, I should be more judicious in this regard (not enough hours in the day!)

What other series are you looking at? Maybe that's the best way to approach this -- I forgot which ones you are considering...

Dane - Site Editor - from 2023

Energy Star Rated Windows

I thought you might say that based on other responses I've read, but many were older and I wasn't sure about 2023 prices. This guy first gave us a much higher price and said he could combine it with a large condo order he was about to place. That cut off $8,000 and sounds bogus to me. He also said that Energy Star standards for windows are going to change in a month and several competitors would no longer qualify. Sounds like more BS.

David - Homeowner - from 2023

[Site Editor's Answer]

David, for me, anything over $1K per window calls for additional bids. You might have project specifics that warrant that price, but you'll never really know unless you get a couple more bids. Sunrise makes a great window, but there are lots of other companies that do as well. I don't know specifics in terms of which series don't make the cut and which do -- we're going to have to wait and see what they exact numbers are before we will know the results. Kind of a strange situation if you ask me -- and I think you agree :)

Dane - Site Editor - from 2023

Energy Star Windows

Dane, we appreciate your response (and your expertise) whenever it comes. I filled out the quote request as you suggested. We'll see what else we get - I'm excited. I’m in a suburb of Detroit, MI

I did call OKNA, but they have no representation in Michigan. (Okna Reviews) There is a Soft-Lite dealer in a more upscale suburb than ours that is not too far away.

I like to be a good steward of the things I’ve been given, and and typically appreciate and support the efforts and work of environmental efforts, like Energy Star. I’m also aware that that there is "point of diminishing return” when it comes to efficiency.

Given that purchasing an Energy Star window is a must for us, what is your recommendation on attempting to select a window that complies with the new version 7 specification going to effect this October, or selecting a window in Energy Star’s 2023 “Most Efficient” ESME pro.

Anne - Homeowner - from 2023

[Site Editor's Answer]

Anne, I would hope that most of my recommendations would meet the new Energy Star guidelines, however I’ve been amazed by some of the requirements — although there are lots of regions and each one has different requirements. At the end of the day, I would always go with a top tier brand and series — and agin, these should meet the requirements.

Dane - Site Editor - from 2023

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